Anatomy Review Flashcards
List the three parts of the ear in order
Outer, Middle, Inner ear
What are the four functions of the outer ear?
- Pinna & External auditory meatus houses there
- It collects & directs sound waves to the tympanic membrane
- Gives directional ques
- Has a resonance which provides an increase in sound pressure 2-7kHz
What part of the outer ear should you know?
Crus (Helix), Tragus, Lobule, Concha
What’s another name for the ear canal?
External auditory meatus
Where does the EAM start and end?
From the pinna to the tympanic membrane
What is the texture of the EAM?
The outer portion is cartilaginous, and the inner portion is bony
Where is ear wax formed?
In the EAM but towards the outer portion
What makes our ear wax move out of our ears?
There are cilia located in the outer portion
What makes up the middle ear?
Tympanic membrane and the ossicles
Name the ossicles in order
Malleus, Incus, & Stapes
What is the main function of the middle ear?
To overcome the impedance mismatch between the air-filled auditory canal and fluid filled cochlea
What is the size difference between the eardrum & stapes?
The eardrum is bigger than the stapes footplate, so more pressure is applied on the stapes
The tympanic membrane has how many layers of tissue?
Three
Where is the umbo located?
Tympanic membrane and it’s the head of the malleus
Where is the “cone of light located”?
In the Tympanic membrane
What is the “cone of light”?
It’s a light reflex that’s on the bottom left or bottom right
What does the reflection mean on a TM?
That it is healthy
What are the smallest bones in the human body?
The Ossicles: Malleus, Incus, & Stapes
What’s the purpose of the inner ear?
Houses hearing and balance
What structure makes up the inner ear?
Cochlea, 8th Nerve, Semicircular Canals, & Oval Window
What does the footplate of the stapes sit on?
The oval window
The inner ear has a…
Fluid-filled cochlea
What overcomes the impedance?
The ossicles
What pertains to audition?
The organ of corti
What makes up the organ of corti?
- 3 rows of inner hair cells
- 1 row of outer hair cells
- The tectorial membrane where shearing action occurs
What causes the shearing action?
When vibration causes the stereocilia to bend and rub against the tectorial membrane
What is responsible for the different tones we hear?
Our cochlea is tonotopically organized. As you travel along the cochlea, we go from H-L frequency
What doesn’t the cochlea do?
Process signals
What does the cochlea do?
Sends the signal to our brain
List the Central Auditory Pathway stops in order
- Ventral Cochlear Nucleus
- Superior Olivary Nucleus
- Lateral Lemniscus
- Inferior Colliculus
- Medial Geniculate Body
- Primary Auditory Cortex
What is the pathway of sound?
Outer ear - Middle Ear - Inner Ear - VIIIth Nerve to Brain
What is air conduction?
It’s how sound is heard in real life environments
Where does air conduction pass?
Pass through the outer, middle, & inner ear to the brain
What does bone conduction stimulate
It directly stimulates the cochlea through vibration of temporal bone
What does bone conduction bypass?
Outer & Middle ear
What are the three types of HL?
- Conductive HL
- Sensorineural HL
- Mixed HL
What is a conductive HL?
A barrier/impairment to sound present in the outer/middle ear
How can conductive HL be assessed?
Through air conduction
When is hearing normal for conductive HL?
When assessed through bone conductive (because bone conduction stimulates the cochlea & this where hearing is functionally normally)
What is a sensorineural HL?
Impairment is present in cochlea/VIIIth nerve
How can sensorineural be assessed?
Through air & bone conduction and the levels are the same
What is a mixed hearing loss?
An impairment/barrier shown in both outer/middle ear & cochlea/nerve
When is HL noted for a Mixed Hearing Loss?
When assessed by air & bone conduction
In Mixed Hearing Loss, which is worse? Air or Bone?
Air is worse
When Mixed Hearing Loss is being assessed by bone conduction, what happens?
Impairment in the outer/middle ear is ADDED to the impairment in cochlea/nerve
